According to Brooke, her mother would take her into bars when she was a baby and later in life would be drunk by the time Brooke got home from school. Brooke also claims that she staged an intervention for her mother when she was just 13.
"You know, it's like a puppy that wants to protect their food source you know. I had to keep my mom alive," Brooke tells ET. "I just learned at a very early age to be the adult."
Part of being an adult may have included covering for her mom. In a 1981 interview with ET, Brooke -- just 15 at the time -- gushed about working with her mother, despite growing criticism concerning the provocative roles she was allowed to take on at a young age.
"I feel I'm lucky she's my manager too. I get that sort of extra attention," Brooke told us three decades ago after playing a child prostitute in the film Pretty Baby. "It's like we're roommates or sisters so we're lucky."
Today, Brooke explained to us what she was thinking at the time.
"I was so afraid that people were going to not understand how she struggled with drinking," Brooke says. "I was so afraid that she would look like a liar, or that I would, and I was so afraid that she wouldn't be okay, so that person is desperately trying to keep her mother alive."
Teri Shields passed away on October 31, 2012 in New York City at age 79 after a long illness related to dementia.
Now, Brooke is a mother herself, raising two "self-confident" young daughters with her second husband, screenwriter Chris Henchy.
There Was a Little Girl: The Real Story of My Mother and Me is out out now. Watch the video for a speed round of word association regarding Brooke's past loves Dean Cain, Liam Neeson, John Travolta and ex-husband Andre Agassi.